Spray nozzle



United States Patent SPRAY NOZZLE Israel H. Marantz, Forest Hills, N.Y., assignor tp Columbia Cable & Electric Corporation, a corporation ofNew York Application May 3, 1952, Serial No. 285,953

9 Claims. (Cl. 299--28.6)

This invention relates to spray nozzles, more particularly of the typeto spray a stream of metallic particles.

As conducive to an understanding of the invention, it is noted thatwhere heat is applied to metal particles for only an extremely shortperiod of time, unless such heat is extremely high, some of theparticles may not be transformed to the highly plastic state requiredfor adherence to the article on which they are sprayed.

Where the heat is applied only to the outer periphery of a stream ofparticles, those particles at the core of the stream will receive lessheat than those at such outer periphery, with the result that some ofthe particles may not be transformed to the desired plastic state withthe resultant poor adherence thereof to the article being sprayed.

Where a stream of particles is propelled through a heated nozzle and theheated particles adhere to the bore surface of the nozzle, the latter islikely to clog with resultant inoperativeness thereof.

Where the stream of heated particles is not guided as it emerges fromthe spray nozzle, it may spread out with the result that some of theparticles will not strike the article being sprayed, with resultant lowefficiency of the spraying operation. In addition, if the particles andthe article being sprayed are at such a high temperature that theparticles remain highly plastic for any considerable time after theystrike such article, the particles are likely to flow off the latterwith resultant poor coating thereof.

It is accordingly among the objects of the invention to provide a spraynozzle through which a stream of particles may be propelled and whichprovides for uniform heating at a relatively high temperature of all ofthe particles passing therethrough so that all of such particles will betransformed to a highly plastic state and will emerge from the outlet ofthe nozzle as a stream of such plastic particles thereby assuringuniform adherence to the object being sprayed, which nozzle isrelatively light in weight, compact and sturdy and has but few parts,-none of which are likely to become deranged and which is not likely tobecome clogged even with long, continuous use, and which directs theparticles emerging from the nozzle to a localized area to provide forefficient application to the article being sprayed, with substantiallyno Waste, and which provides a cooling action for the plastic particlesas they emerge from the nozzle so that they will more readily adhere tothe article being sprayed and will not flow off the latter.

According to the invention, a stream of particles is propelled through atube which is heated to a sufiiciently high temperature to transform theparticles passing therethrough to a highly plastic state. Gas, underpressure, is forced through the tube in direction substantially at rightangles to the path of movement of the stream of particles, therebyagitating such particles for uniform application of heat thereto andpreventing adice herence of such particles to the bore surface of thetube. The stream of plastic particles emerging from the outlet of thenozzle is restrained from spreading by means of an encompassing gasstream which also serves to cool the particles.

In the accompanying drawings in which are shown one or more of variouspossible embodiments of the several features of the invention,

Fig. 1 is a longitudinal sectional View of one embodiment of the nozzle,

Fig. 2 is a view similar to Fig. l of another embodiment thereof,

Fig. 3 is a front view of the nozzle tip taken along line 3-3 of Fig. l,and

Fig. 4 is a front view of another embodiment of the nozzle tip.

Referring now to the drawings, the nozzle shown in Fig. 1 comprises atip 10 substantially circular as shown and desirably having an axialbore 11 therethrough with an outlet 12. The nose end 13 of the tip isdesirably in the shape of a truncated cone and a plurality of gas outletbores 14 extending through said nose and converging at their outlet endsas at 15 adjacent the outlet 12 of bore 11 terminate vat their innerends 17 in an annular chamber 18 in said tip.

Associated with the tip 113 and longitudinally spaced therefrom is themain body or base 21 of the nozzle. The body 21 which is substantiallycylindrical, desirably has' an axial bore 22 therethrough longitudinallyaligned with the bore 11 in tip 10.

Extending between the opposed faces 24 and 25 of I the tip 10 and body21 is a tubular casing 26 of any suitable rigid material andillustratively of metal. In orderto support the casing 26, the ends 27and 28 thereof respectively encompass an inwardly extending annularflange 29 on tip .10 and a reduced portion 30 on body portion 21 whichdefines a shoulder 31. In order to insulate the casing 26 from the tip10 and body 21, an annular insulating washer 32 which may be, forexample, of ceramic material, is interposed between the flange 28 andshoulder 31 and the adjacent end 27, 28 of casing 26.

Coaxial with casing 26 and encompassed thereby is a tube 33 of porousmaterial preferably of a sintered metal which may be of nickel alloysuch as is commercially known as Inconel. The ends 34 of tube 33desirably are positioned in the bores 11 and 22 respectively of tip 10and body portion 22 at the opposed faces 24 and 25 thereof and abutagainst shoulders 36 formed in said bores.

Means are desirably provided to retain the tube 33 and the casing 26 infixed position with respect to tip 10 and body 21. Although any suitablemeans may be provided for this purpose, in the illustrative embodimentherein shown, the tip 10 and the body portion 21 each has a plurality oflugs 41 and 42 respectively, preferably formed integral therewith andextending radially outward therefrom.

Pairs of lugs 41 and 42 on the tip 10 and body portion 21 arelongitudinally aligned and a bolt 43 extends through bores 44 in saidlugs so that when nuts 45 on said bolts are tightened the tip 10 and thebody portion 21 will be drawn together securely to retain the casing 26and tube 33 therebetween.

Desirably the bolts 43 are insulated from the tip 10 and body portion 21by means of bushings 46 of insulating material such as ceramic whichencompasses that portion of the bolt 43 extending through the bores 44.

With the construction above described, the metal tip 10 and the metalbody 21 are electrically insulated from each other by the insulatingwashers 32 and bushings 46.

3 Thus, when a heating transformer (not shown) is connected by leads 47and .48 to lugs 41 and- 42 on tip and body portion 21 respectively,current will flow through tube 33 which otters a relatively lowresistance to the flow of current therethrough, and the tube 33 willheat up to the desired temperature.

Means are provided to eject a powder, which may be a metal such as zinc,through tube 33, to be heated thereby to a highly plastic state almostreaching the molten condition for adherence to an object to be sprayed.

Although the powder may be injected into tube 33 in any suitable manner,in the embodiment herein shown, the axial bore 22 in body portion 21desirably has a plug 51. aflixed therein, said plug having asubstantially conical nose 52 and desirably having an axial bore 53therethrough of enlarged diameter as at 54 at its rear end.

Although the plug 51 may be afiixed in bore 22 in any suitable manner,in the embodiment herein shown, the plug 51 is externally threaded sothat it may be screwed into the correspondingly threaded bore, thelatter desirably having a closure plug 55 screwed in the end 56 thereof.

Extending longitudinally through body portion 21 adjacent the surface 57thereof is a bore 58, the inlet end 59 of which is connected by afitting 61 to line 62 from a source of compressed gas (not shown).

In order to supply such compressed gas to bore 22, a transversepassageway 63 is provided between bores 58 and 22. The flow of gasthrough passageway 63 is desirably controlled by a valve 64 preferablyof the needle type. I

This valve desirably comprises a hollow screw 65 threaded into atransverse cavity 66 in body portion 21 and retaining a packing 67against the floor of said cavity to provide a seal. A valve adjustmentscrew 69 threaded through screw 65 desirably has its inner end '71conformed as a valve head which may hen-loved against a seatingconformation 72 at the outer end of passageway 63 to seal the latter.Thus depending upon the spacing between screw end 71 and seat 72, thefiow of gas into passageway 63 may be regulated.

The portion of bore 22 in body portion 23. adjacent the conical nose ofplug 53 desirably tapers so that the bore 22 is of reduced diameter asat 74 adjacent the inlet end 75 of tube 33. the conical end 52 of plug53 is the outlet end 76 of a powder feed passageway 77 which may beconnected to a source of powder (not shown) by means of a feed tube 73connected by fitting 79 to the inlet of said passageway 77.

The outlet 81 of bore 58 is desirably connected to annular chamber 1% bymeans of a tube 82,, preferably of heat resistant, non-conductingmaterial such as rubber or asbestos. Tube 82 is connected at one end bya fitting 83 to outlet 81 and at its other end by fitting 84 to an inletport 84 formed in a boss 85 formed integral with tip lil, said port 3idesirably being connected by passageway 35 to chamber .18. Thus when gasis forced into chamber 18, it will pass through passageway 37 into thesubstantially gas-tight chamber 35 formed between casing 26 and tube 33.

Suitable means are desirably provided to control the flow of gas throughthe wall of porous tube 33 Such means may comprise a needle valve 89substantially identical to valve 6% and comprising a screw 91 of largerdiameter than bore 58 and having a valve head 92 rovable toward and awayfrom a seat 93 formed in the wall of bore 53.

In the operation of the spray nozzle shown in Figs. 1 and 3, the line 73is connected to a source of powder p'articlcssuch as zinc. The line 62is connected to a source of gas under pressure, such gas being air orneutral gas. The power to the heating transformer (not shown) is turnedon so that current will pass through the tube 33 which will provide alow resistance path for the current Extending into bore 22 adjacent 4and heat up to a temperature, illustratively in the order of 2,500 G.

The valve 64 is adjusted to provide a flow of gas from line 62, throughbore 58, passageway 63 into bore 22 and thence through bore 53 ofbushing 51. By reason of the relatively small diameter bore 53, the gasunder pressure will be forced therethrough at a high velocity therebycreating a suction in the reduced portion 74 of bore 22 adjacent outlet76.

Such suction will draw the powder particles through passageway 77 andsuch mixture of gas and powder, by reason of the high velocity of thegas discharged through the bore 53 of plug 51, will be propelled throughthe length of tube 33 and out of outlet 12 of tip 10. By reason of thelength of the heated tube 33, suflicient time is provided for theapplication of heat to the particles to insure softening thereof to ahighly plastic though not molten condition and the plastic particleswill emerge from outlet 12 as a spray.

Uniform application of heat to all of the particles is ensured by thefact that as they pass through the tube 33 they will be violentlyagitated by the flow of gas through the porous tube 33 at substantiallyright angles to the path of movement of the particles therethrough. Thusthe particles at the core of the stream passing through the tube andnormally most remote from the heated wall thereof will be moved towardsuch wall for application of heat thereto. By reason of such gas flowthrough the wall of tube 33 the plastic particles will be prevented fromadhering to the bore surface thereof which would cause clogging of thetube and inoperativeness of the nozzle. By adjusting the valve 64control is afforded of the flow of gas under pressure through tube 82,passageway 86 into annular chamber 18 and thence through passageway 8'7into the chamber 83 encompassing tube 33.

By reason of the converging passageways 14 connected to annular chamber13, excessive spreading of the spray emerging from outlet 12 of tip Illis prevented. Thus the gas under pressure in annular chamber 18 willemerge as high velocity jets from the outlets 15 of passageways 14 andstrike the periphery of the stream of particles and gas emerging fromoutlet 12 thereby substantially preventing spreading of such stream. Inaddition, as the gas emerging from outlets 15 is relatively cool, as theheated particles strike the article being sprayed they will rapidly cooland congeal thereby preventing dripping of such plastic particles fromthe article and insuring adherence of such particles thereto.

The embodiment of the spray nozzle shown in Fig. 2 is identical in manyrespects to the nozzle shown in Figs. 1 and 3 and corresponding partshave the same reference numerals primed.

As shown in Fig. 2, an inductive coil 1491. is positioned in casing 26'encompassing the metal tube 33' so that when a source of alternatingcurrent is applied to the terminals 1G2 and 1&3 of the coil, the inducedcurrents will heat the tube 33 to the temperature required.

The nozzle shown in Fig. 2 also utilizes a powder feed which differsfrom that of the nozzle shown in Fig. 1.

Thus, a mixture of powder particles and gas are injected into bore 22'from a suitable source (not shown) connected to the inlet 56 of bore 22.The stream of powder and gas will pass through the heated tube 33' andbe agitated by the gas flowing through the porous wall of the tube fromchamber 18.

As the operation of the nozzle shown in Fig. 2 is identical to thatshown in Fig. 1 except for the modifications above pointed out, it willnot be further described.

Although as shown in Fig. 3, the tip ends of the nozzles areillustratively circularand the outlets 15 are arranged in a circle aboutthe outlet 12 of tip 10, it is of course to be understood that thenozzle could be of any desired shape such as a narrow slot shown in Fig.4 and the outlets 106 encompassing the outlet 105 could have acorresponding contour.

With the nozzles above d scribed, uniform application of heat to all theparticles passing therethrough is assured so that when such particlesstrike the article being sprayed they will be in the required state foradherence thereto. The guiding and cooling effect of the jets of gasencompassing the outlet of the nozzles prevents spreading of the streamand thereby eliminates waste and provides a cooling action which willsubstantially prevent dripping of the plastic particles from the sprayedobject.

As many changes could be made in the above construction, and manyapparently widely different embodiments of this invention could be madewithout departing from the scope of the claims, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent of the United States is:

1. A spray nozzle comprising a porous tube having an inlet and outlet,means to heat substantially the entire length of said tube, and means toforce gas under pressure through the porous wall of said tube, wherebywhen particles are forced under pressure into the inlet of said tube,the gas forced through the wall of the tube will agitate such particlesand will prevent the latter from adhering to the bore of such tube, suchparticles emerging from the outlet of the tube as a spray of highlyplastic particles.

2. The combination set forth in claim 1 in which said porous tube is ofmetal whereby when a source of current is applied to the ends of thetube the latter will become heated.

3. A spray nozzle comprising a porous tube having an inlet and anoutlet, a tip and a body portion at the outlet and inlet ends of saidtube respectively, said tip and body portions having bores therethroughin communication with said outlet and inlet respectively, means to heatsubstantially the entire length of said tube, a gas chamber encompassingsaid tube between said tip and said body portion, a chamber in said tipadjacent the bore therethrough, a passageway from said tip chamber tosaid gas chamber, means to charge said tip chamber with gas underpressure for flow of such gas through said passageway into said gaschamber and through the porous wall of said tube whereby when particlesare forced under pressure through the bore in said body portion into theinlet of said tube, the gas forced through the wall of said tube willagitate such particles and will prevent the latter from adhering to thebore of said tube, such particles emerging from the bore of said tip asa spray of highly plastic particles.

4. The combination set forth in claim 3 in which said tip has aplurality of gas passageways therein having their inlets in said tipchamber, the outlets of said passageways being arranged around theoutlet of the tip bore and directed toward a'common point whereby thegas in said tip chamber will emerge from said outlets and abut againstthe periphery of said stream to prevent spreading thereof.

5. A spray nozzle comprising a porous tube having an inlet and anoutlet, a tip and a body portion at the outlet and inlet ends of saidtube respectively, said tip and body portions having bores therethroughin communication with said outlet and inlet respectively, means to heatsaid tube, a gas chamber encompassing said tube between said tip andsaid body portion, a chamber in said tip adjacent the bore therethrough,a passageway from said tip chamber to said gas chamber, means to chargesaid tip chamber with gas under pressure for flow of such gas throughsaid passageway into said gas chamber and through the porous wall ofsaid tube, a feed passageway in said body portion having an outletleading into the bore therein, means to force a stream of gas past theoutlet of said feed passageway and into the tube to create a suction inthe bore in said body portion adjacent said outlet, whereby when asource of particles are connected to said feed passageway they will beforced through said tube and will pass through the latter, the gasforced through the wall of the tube agitating such particles andpreventing the latter from adhering to the bore of said tube, suchparticles emerging from the bore of said tip as a spray of highlyplastic particles.

6. The combination set forth in claim 5 in which the means to create asuction in the bore of said body portion comprises a plug having a boretherethrough longitudinally aligned with said tube, the outlet of saidplug being positioned adjacent the outlet of said feed passageway, andmeans to connect a source of gas under pressure to the inlet end of saidplug bore.

7. The combination set forth in claim 5 in which said gas chambercomprises a cylindrical casing encompassing said tube and spacedtherefrom, said casing being affixed at its ends to the opposed faces ofsaid tip and said body portion.

8. The combination set forth in claim 5 in which said gas chambercomprises as a cylindrical casing encompassing said tube and spacedtherefrom, said casing being affixed at its ends to the opposed faces ofsaid tip and said body portion, said tip and said body portion being ofmetal, and insulating means are positioned between the ends of thecasing and the adjacent tip and body portion.

9. The combination set forth in claim 5 in which said body portion has abore therethrough having an outlet and an inletfor connection of a gasline thereinto, valve means controlling the flow of gas through saidbore and a tube connecting the outlet of said bore to said tip chamber.

References Cited in the file of this patent UNITED STATES PATENTS1,047,636 Horn Dec. 17, 1912 1,575,152 Battista Mar. 2, 1926 1,779,850Maurer Oct. 28, 1930 1,794,215 Titus Feb. 24, 1931 2,158,238 Hvid May16, 1939 2,269,057 Jenkins Ian. 6, 1942 2,434,911 Denyssen Jan. 27, 19482,436,335 Simonsen Feb. 17, 1948 2,544,259 Duccini et al Mar. 6, 19512,551,078 Wing May 1, 1951 FOREIGN PATENTS 236,241 Switzerland Jan. 31,1945 664,930 Great Britain Jan. 16, 1952

